>>I switched the router on and off again but the printer is still greyed out.
In my reply above I was pointing that switching the router on and off would BREAK the wi fi connection to the printer, not fix it !
This has sometimes happened to me. I may have a working wi fi connection to my printer, but then turn off the router for some reason, and the printer wi fi connection is lost.
When you first set up the printer the connection may have been fine, so the printer would appear in your list of devices, and it would get the properties.
But then (for some reason) the wi fi connection was lost, but your computer still shows the printer icon, but greyed out, and still has the properties from when it was first set up.
As I said above, you need to reinstall the printer to re-establish the wi fi connection.